Mercurial > hg > truffle
annotate src/share/vm/utilities/workgroup.cpp @ 17949:487f09bf44e0
8040803: G1: Concurrent mark hangs when mark stack overflows
Reviewed-by: brutisso, ehelin
| author | pliden |
|---|---|
| date | Wed, 14 May 2014 13:32:44 +0200 |
| parents | 78bbf4d43a14 |
| children |
| rev | line source |
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| 0 | 1 /* |
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2 * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved. |
| 0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
|
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
| 0 | 22 * |
| 23 */ | |
| 24 | |
| 1972 | 25 #include "precompiled.hpp" |
| 26 #include "memory/allocation.hpp" | |
| 27 #include "memory/allocation.inline.hpp" | |
| 28 #include "runtime/os.hpp" | |
| 29 #include "utilities/workgroup.hpp" | |
| 0 | 30 |
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31 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC |
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32 |
| 0 | 33 // Definitions of WorkGang methods. |
| 34 | |
| 35 AbstractWorkGang::AbstractWorkGang(const char* name, | |
| 342 | 36 bool are_GC_task_threads, |
| 37 bool are_ConcurrentGC_threads) : | |
| 0 | 38 _name(name), |
| 342 | 39 _are_GC_task_threads(are_GC_task_threads), |
| 40 _are_ConcurrentGC_threads(are_ConcurrentGC_threads) { | |
| 41 | |
| 42 assert(!(are_GC_task_threads && are_ConcurrentGC_threads), | |
| 43 "They cannot both be STW GC and Concurrent threads" ); | |
| 44 | |
| 0 | 45 // Other initialization. |
| 46 _monitor = new Monitor(/* priority */ Mutex::leaf, | |
| 47 /* name */ "WorkGroup monitor", | |
| 342 | 48 /* allow_vm_block */ are_GC_task_threads); |
| 0 | 49 assert(monitor() != NULL, "Failed to allocate monitor"); |
| 50 _terminate = false; | |
| 51 _task = NULL; | |
| 52 _sequence_number = 0; | |
| 53 _started_workers = 0; | |
| 54 _finished_workers = 0; | |
| 55 } | |
| 56 | |
| 57 WorkGang::WorkGang(const char* name, | |
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58 uint workers, |
| 342 | 59 bool are_GC_task_threads, |
| 60 bool are_ConcurrentGC_threads) : | |
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61 AbstractWorkGang(name, are_GC_task_threads, are_ConcurrentGC_threads) { |
| 0 | 62 _total_workers = workers; |
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63 } |
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64 |
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65 GangWorker* WorkGang::allocate_worker(uint which) { |
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66 GangWorker* new_worker = new GangWorker(this, which); |
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67 return new_worker; |
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68 } |
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69 |
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70 // The current implementation will exit if the allocation |
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71 // of any worker fails. Still, return a boolean so that |
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72 // a future implementation can possibly do a partial |
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73 // initialization of the workers and report such to the |
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74 // caller. |
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75 bool WorkGang::initialize_workers() { |
| 342 | 76 |
| 0 | 77 if (TraceWorkGang) { |
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78 tty->print_cr("Constructing work gang %s with %d threads", |
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79 name(), |
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80 total_workers()); |
| 0 | 81 } |
| 6197 | 82 _gang_workers = NEW_C_HEAP_ARRAY(GangWorker*, total_workers(), mtInternal); |
| 342 | 83 if (gang_workers() == NULL) { |
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84 vm_exit_out_of_memory(0, OOM_MALLOC_ERROR, "Cannot create GangWorker array."); |
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85 return false; |
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86 } |
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87 os::ThreadType worker_type; |
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88 if (are_ConcurrentGC_threads()) { |
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89 worker_type = os::cgc_thread; |
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90 } else { |
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91 worker_type = os::pgc_thread; |
| 342 | 92 } |
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93 for (uint worker = 0; worker < total_workers(); worker += 1) { |
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94 GangWorker* new_worker = allocate_worker(worker); |
| 0 | 95 assert(new_worker != NULL, "Failed to allocate GangWorker"); |
| 96 _gang_workers[worker] = new_worker; | |
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97 if (new_worker == NULL || !os::create_thread(new_worker, worker_type)) { |
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98 vm_exit_out_of_memory(0, OOM_MALLOC_ERROR, |
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99 "Cannot create worker GC thread. Out of system resources."); |
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100 return false; |
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101 } |
| 0 | 102 if (!DisableStartThread) { |
| 103 os::start_thread(new_worker); | |
| 104 } | |
| 105 } | |
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106 return true; |
| 0 | 107 } |
| 108 | |
| 109 AbstractWorkGang::~AbstractWorkGang() { | |
| 110 if (TraceWorkGang) { | |
| 111 tty->print_cr("Destructing work gang %s", name()); | |
| 112 } | |
| 113 stop(); // stop all the workers | |
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114 for (uint worker = 0; worker < total_workers(); worker += 1) { |
| 0 | 115 delete gang_worker(worker); |
| 116 } | |
| 117 delete gang_workers(); | |
| 118 delete monitor(); | |
| 119 } | |
| 120 | |
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121 GangWorker* AbstractWorkGang::gang_worker(uint i) const { |
| 0 | 122 // Array index bounds checking. |
| 123 GangWorker* result = NULL; | |
| 124 assert(gang_workers() != NULL, "No workers for indexing"); | |
| 125 assert(((i >= 0) && (i < total_workers())), "Worker index out of bounds"); | |
| 126 result = _gang_workers[i]; | |
| 127 assert(result != NULL, "Indexing to null worker"); | |
| 128 return result; | |
| 129 } | |
| 130 | |
| 131 void WorkGang::run_task(AbstractGangTask* task) { | |
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132 run_task(task, total_workers()); |
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133 } |
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134 |
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135 void WorkGang::run_task(AbstractGangTask* task, uint no_of_parallel_workers) { |
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136 task->set_for_termination(no_of_parallel_workers); |
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137 |
| 0 | 138 // This thread is executed by the VM thread which does not block |
| 139 // on ordinary MutexLocker's. | |
| 140 MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag); | |
| 141 if (TraceWorkGang) { | |
| 142 tty->print_cr("Running work gang %s task %s", name(), task->name()); | |
| 143 } | |
| 144 // Tell all the workers to run a task. | |
| 145 assert(task != NULL, "Running a null task"); | |
| 146 // Initialize. | |
| 147 _task = task; | |
| 148 _sequence_number += 1; | |
| 149 _started_workers = 0; | |
| 150 _finished_workers = 0; | |
| 151 // Tell the workers to get to work. | |
| 152 monitor()->notify_all(); | |
| 153 // Wait for them to be finished | |
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154 while (finished_workers() < no_of_parallel_workers) { |
| 0 | 155 if (TraceWorkGang) { |
| 156 tty->print_cr("Waiting in work gang %s: %d/%d finished sequence %d", | |
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157 name(), finished_workers(), no_of_parallel_workers, |
| 0 | 158 _sequence_number); |
| 159 } | |
| 160 monitor()->wait(/* no_safepoint_check */ true); | |
| 161 } | |
| 162 _task = NULL; | |
| 163 if (TraceWorkGang) { | |
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164 tty->print_cr("\nFinished work gang %s: %d/%d sequence %d", |
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165 name(), finished_workers(), no_of_parallel_workers, |
| 0 | 166 _sequence_number); |
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167 Thread* me = Thread::current(); |
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168 tty->print_cr(" T: 0x%x VM_thread: %d", me, me->is_VM_thread()); |
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169 } |
| 0 | 170 } |
| 171 | |
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172 void FlexibleWorkGang::run_task(AbstractGangTask* task) { |
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173 // If active_workers() is passed, _finished_workers |
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174 // must only be incremented for workers that find non_null |
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175 // work (as opposed to all those that just check that the |
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176 // task is not null). |
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177 WorkGang::run_task(task, (uint) active_workers()); |
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178 } |
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179 |
| 0 | 180 void AbstractWorkGang::stop() { |
| 181 // Tell all workers to terminate, then wait for them to become inactive. | |
| 182 MutexLockerEx ml(monitor(), Mutex::_no_safepoint_check_flag); | |
| 183 if (TraceWorkGang) { | |
| 184 tty->print_cr("Stopping work gang %s task %s", name(), task()->name()); | |
| 185 } | |
| 186 _task = NULL; | |
| 187 _terminate = true; | |
| 188 monitor()->notify_all(); | |
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189 while (finished_workers() < active_workers()) { |
| 0 | 190 if (TraceWorkGang) { |
| 191 tty->print_cr("Waiting in work gang %s: %d/%d finished", | |
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192 name(), finished_workers(), active_workers()); |
| 0 | 193 } |
| 194 monitor()->wait(/* no_safepoint_check */ true); | |
| 195 } | |
| 196 } | |
| 197 | |
| 198 void AbstractWorkGang::internal_worker_poll(WorkData* data) const { | |
| 199 assert(monitor()->owned_by_self(), "worker_poll is an internal method"); | |
| 200 assert(data != NULL, "worker data is null"); | |
| 201 data->set_terminate(terminate()); | |
| 202 data->set_task(task()); | |
| 203 data->set_sequence_number(sequence_number()); | |
| 204 } | |
| 205 | |
| 206 void AbstractWorkGang::internal_note_start() { | |
| 207 assert(monitor()->owned_by_self(), "note_finish is an internal method"); | |
| 208 _started_workers += 1; | |
| 209 } | |
| 210 | |
| 211 void AbstractWorkGang::internal_note_finish() { | |
| 212 assert(monitor()->owned_by_self(), "note_finish is an internal method"); | |
| 213 _finished_workers += 1; | |
| 214 } | |
| 215 | |
| 216 void AbstractWorkGang::print_worker_threads_on(outputStream* st) const { | |
| 217 uint num_thr = total_workers(); | |
| 218 for (uint i = 0; i < num_thr; i++) { | |
| 219 gang_worker(i)->print_on(st); | |
| 220 st->cr(); | |
| 221 } | |
| 222 } | |
| 223 | |
| 224 void AbstractWorkGang::threads_do(ThreadClosure* tc) const { | |
| 225 assert(tc != NULL, "Null ThreadClosure"); | |
| 226 uint num_thr = total_workers(); | |
| 227 for (uint i = 0; i < num_thr; i++) { | |
| 228 tc->do_thread(gang_worker(i)); | |
| 229 } | |
| 230 } | |
| 231 | |
| 232 // GangWorker methods. | |
| 233 | |
| 234 GangWorker::GangWorker(AbstractWorkGang* gang, uint id) { | |
| 235 _gang = gang; | |
| 236 set_id(id); | |
| 237 set_name("Gang worker#%d (%s)", id, gang->name()); | |
| 238 } | |
| 239 | |
| 240 void GangWorker::run() { | |
| 241 initialize(); | |
| 242 loop(); | |
| 243 } | |
| 244 | |
| 245 void GangWorker::initialize() { | |
| 246 this->initialize_thread_local_storage(); | |
| 6197 | 247 this->record_stack_base_and_size(); |
| 0 | 248 assert(_gang != NULL, "No gang to run in"); |
| 249 os::set_priority(this, NearMaxPriority); | |
| 250 if (TraceWorkGang) { | |
| 251 tty->print_cr("Running gang worker for gang %s id %d", | |
| 252 gang()->name(), id()); | |
| 253 } | |
| 254 // The VM thread should not execute here because MutexLocker's are used | |
| 255 // as (opposed to MutexLockerEx's). | |
| 256 assert(!Thread::current()->is_VM_thread(), "VM thread should not be part" | |
| 257 " of a work gang"); | |
| 258 } | |
| 259 | |
| 260 void GangWorker::loop() { | |
| 261 int previous_sequence_number = 0; | |
| 262 Monitor* gang_monitor = gang()->monitor(); | |
| 263 for ( ; /* !terminate() */; ) { | |
| 264 WorkData data; | |
| 265 int part; // Initialized below. | |
| 266 { | |
| 267 // Grab the gang mutex. | |
| 268 MutexLocker ml(gang_monitor); | |
| 269 // Wait for something to do. | |
| 270 // Polling outside the while { wait } avoids missed notifies | |
| 271 // in the outer loop. | |
| 272 gang()->internal_worker_poll(&data); | |
| 273 if (TraceWorkGang) { | |
| 274 tty->print("Polled outside for work in gang %s worker %d", | |
| 275 gang()->name(), id()); | |
| 276 tty->print(" terminate: %s", | |
| 277 data.terminate() ? "true" : "false"); | |
| 278 tty->print(" sequence: %d (prev: %d)", | |
| 279 data.sequence_number(), previous_sequence_number); | |
| 280 if (data.task() != NULL) { | |
| 281 tty->print(" task: %s", data.task()->name()); | |
| 282 } else { | |
| 283 tty->print(" task: NULL"); | |
| 284 } | |
| 285 tty->cr(); | |
| 286 } | |
| 287 for ( ; /* break or return */; ) { | |
| 288 // Terminate if requested. | |
| 289 if (data.terminate()) { | |
| 290 gang()->internal_note_finish(); | |
| 291 gang_monitor->notify_all(); | |
| 292 return; | |
| 293 } | |
| 294 // Check for new work. | |
| 295 if ((data.task() != NULL) && | |
| 296 (data.sequence_number() != previous_sequence_number)) { | |
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297 if (gang()->needs_more_workers()) { |
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298 gang()->internal_note_start(); |
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299 gang_monitor->notify_all(); |
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300 part = gang()->started_workers() - 1; |
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301 break; |
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302 } |
| 0 | 303 } |
| 304 // Nothing to do. | |
| 305 gang_monitor->wait(/* no_safepoint_check */ true); | |
| 306 gang()->internal_worker_poll(&data); | |
| 307 if (TraceWorkGang) { | |
| 308 tty->print("Polled inside for work in gang %s worker %d", | |
| 309 gang()->name(), id()); | |
| 310 tty->print(" terminate: %s", | |
| 311 data.terminate() ? "true" : "false"); | |
| 312 tty->print(" sequence: %d (prev: %d)", | |
| 313 data.sequence_number(), previous_sequence_number); | |
| 314 if (data.task() != NULL) { | |
| 315 tty->print(" task: %s", data.task()->name()); | |
| 316 } else { | |
| 317 tty->print(" task: NULL"); | |
| 318 } | |
| 319 tty->cr(); | |
| 320 } | |
| 321 } | |
| 322 // Drop gang mutex. | |
| 323 } | |
| 324 if (TraceWorkGang) { | |
| 325 tty->print("Work for work gang %s id %d task %s part %d", | |
| 326 gang()->name(), id(), data.task()->name(), part); | |
| 327 } | |
| 328 assert(data.task() != NULL, "Got null task"); | |
| 329 data.task()->work(part); | |
| 330 { | |
| 331 if (TraceWorkGang) { | |
| 332 tty->print("Finish for work gang %s id %d task %s part %d", | |
| 333 gang()->name(), id(), data.task()->name(), part); | |
| 334 } | |
| 335 // Grab the gang mutex. | |
| 336 MutexLocker ml(gang_monitor); | |
| 337 gang()->internal_note_finish(); | |
| 338 // Tell the gang you are done. | |
| 339 gang_monitor->notify_all(); | |
| 340 // Drop the gang mutex. | |
| 341 } | |
| 342 previous_sequence_number = data.sequence_number(); | |
| 343 } | |
| 344 } | |
| 345 | |
| 346 bool GangWorker::is_GC_task_thread() const { | |
| 342 | 347 return gang()->are_GC_task_threads(); |
| 348 } | |
| 349 | |
| 350 bool GangWorker::is_ConcurrentGC_thread() const { | |
| 351 return gang()->are_ConcurrentGC_threads(); | |
| 0 | 352 } |
| 353 | |
| 354 void GangWorker::print_on(outputStream* st) const { | |
| 355 st->print("\"%s\" ", name()); | |
| 356 Thread::print_on(st); | |
| 357 st->cr(); | |
| 358 } | |
| 359 | |
| 360 // Printing methods | |
| 361 | |
| 362 const char* AbstractWorkGang::name() const { | |
| 363 return _name; | |
| 364 } | |
| 365 | |
| 366 #ifndef PRODUCT | |
| 367 | |
| 368 const char* AbstractGangTask::name() const { | |
| 369 return _name; | |
| 370 } | |
| 371 | |
| 372 #endif /* PRODUCT */ | |
| 373 | |
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374 // FlexibleWorkGang |
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375 |
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376 |
| 0 | 377 // *** WorkGangBarrierSync |
| 378 | |
| 379 WorkGangBarrierSync::WorkGangBarrierSync() | |
| 380 : _monitor(Mutex::safepoint, "work gang barrier sync", true), | |
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381 _n_workers(0), _n_completed(0), _should_reset(false), _aborted(false) { |
| 0 | 382 } |
| 383 | |
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384 WorkGangBarrierSync::WorkGangBarrierSync(uint n_workers, const char* name) |
| 0 | 385 : _monitor(Mutex::safepoint, name, true), |
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386 _n_workers(n_workers), _n_completed(0), _should_reset(false), _aborted(false) { |
| 0 | 387 } |
| 388 | |
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389 void WorkGangBarrierSync::set_n_workers(uint n_workers) { |
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390 _n_workers = n_workers; |
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391 _n_completed = 0; |
| 342 | 392 _should_reset = false; |
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393 _aborted = false; |
| 0 | 394 } |
| 395 | |
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396 bool WorkGangBarrierSync::enter() { |
| 0 | 397 MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag); |
| 342 | 398 if (should_reset()) { |
| 399 // The should_reset() was set and we are the first worker to enter | |
| 400 // the sync barrier. We will zero the n_completed() count which | |
| 401 // effectively resets the barrier. | |
| 402 zero_completed(); | |
| 403 set_should_reset(false); | |
| 404 } | |
| 0 | 405 inc_completed(); |
| 406 if (n_completed() == n_workers()) { | |
| 342 | 407 // At this point we would like to reset the barrier to be ready in |
| 408 // case it is used again. However, we cannot set n_completed() to | |
| 409 // 0, even after the notify_all(), given that some other workers | |
| 410 // might still be waiting for n_completed() to become == | |
| 411 // n_workers(). So, if we set n_completed() to 0, those workers | |
| 412 // will get stuck (as they will wake up, see that n_completed() != | |
| 413 // n_workers() and go back to sleep). Instead, we raise the | |
| 414 // should_reset() flag and the barrier will be reset the first | |
| 415 // time a worker enters it again. | |
| 416 set_should_reset(true); | |
| 0 | 417 monitor()->notify_all(); |
| 342 | 418 } else { |
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419 while (n_completed() != n_workers() && !aborted()) { |
| 0 | 420 monitor()->wait(/* no_safepoint_check */ true); |
| 421 } | |
| 422 } | |
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423 return !aborted(); |
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424 } |
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425 |
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426 void WorkGangBarrierSync::abort() { |
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427 MutexLockerEx x(monitor(), Mutex::_no_safepoint_check_flag); |
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428 set_aborted(); |
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429 monitor()->notify_all(); |
| 0 | 430 } |
| 431 | |
| 432 // SubTasksDone functions. | |
| 433 | |
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434 SubTasksDone::SubTasksDone(uint n) : |
| 0 | 435 _n_tasks(n), _n_threads(1), _tasks(NULL) { |
| 6197 | 436 _tasks = NEW_C_HEAP_ARRAY(uint, n, mtInternal); |
| 0 | 437 guarantee(_tasks != NULL, "alloc failure"); |
| 438 clear(); | |
| 439 } | |
| 440 | |
| 441 bool SubTasksDone::valid() { | |
| 442 return _tasks != NULL; | |
| 443 } | |
| 444 | |
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445 void SubTasksDone::set_n_threads(uint t) { |
| 0 | 446 assert(_claimed == 0 || _threads_completed == _n_threads, |
| 447 "should not be called while tasks are being processed!"); | |
| 448 _n_threads = (t == 0 ? 1 : t); | |
| 449 } | |
| 450 | |
| 451 void SubTasksDone::clear() { | |
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452 for (uint i = 0; i < _n_tasks; i++) { |
| 0 | 453 _tasks[i] = 0; |
| 454 } | |
| 455 _threads_completed = 0; | |
| 456 #ifdef ASSERT | |
| 457 _claimed = 0; | |
| 458 #endif | |
| 459 } | |
| 460 | |
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461 bool SubTasksDone::is_task_claimed(uint t) { |
| 0 | 462 assert(0 <= t && t < _n_tasks, "bad task id."); |
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463 uint old = _tasks[t]; |
| 0 | 464 if (old == 0) { |
| 465 old = Atomic::cmpxchg(1, &_tasks[t], 0); | |
| 466 } | |
| 467 assert(_tasks[t] == 1, "What else?"); | |
| 468 bool res = old != 0; | |
| 469 #ifdef ASSERT | |
| 470 if (!res) { | |
| 471 assert(_claimed < _n_tasks, "Too many tasks claimed; missing clear?"); | |
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472 Atomic::inc((volatile jint*) &_claimed); |
| 0 | 473 } |
| 474 #endif | |
| 475 return res; | |
| 476 } | |
| 477 | |
| 478 void SubTasksDone::all_tasks_completed() { | |
| 479 jint observed = _threads_completed; | |
| 480 jint old; | |
| 481 do { | |
| 482 old = observed; | |
| 483 observed = Atomic::cmpxchg(old+1, &_threads_completed, old); | |
| 484 } while (observed != old); | |
| 485 // If this was the last thread checking in, clear the tasks. | |
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486 if (observed+1 == (jint)_n_threads) clear(); |
| 0 | 487 } |
| 488 | |
| 489 | |
| 490 SubTasksDone::~SubTasksDone() { | |
| 6197 | 491 if (_tasks != NULL) FREE_C_HEAP_ARRAY(jint, _tasks, mtInternal); |
| 0 | 492 } |
| 493 | |
| 494 // *** SequentialSubTasksDone | |
| 495 | |
| 496 void SequentialSubTasksDone::clear() { | |
| 497 _n_tasks = _n_claimed = 0; | |
| 498 _n_threads = _n_completed = 0; | |
| 499 } | |
| 500 | |
| 501 bool SequentialSubTasksDone::valid() { | |
| 502 return _n_threads > 0; | |
| 503 } | |
| 504 | |
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505 bool SequentialSubTasksDone::is_task_claimed(uint& t) { |
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506 uint* n_claimed_ptr = &_n_claimed; |
| 0 | 507 t = *n_claimed_ptr; |
| 508 while (t < _n_tasks) { | |
| 509 jint res = Atomic::cmpxchg(t+1, n_claimed_ptr, t); | |
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510 if (res == (jint)t) { |
| 0 | 511 return false; |
| 512 } | |
| 513 t = *n_claimed_ptr; | |
| 514 } | |
| 515 return true; | |
| 516 } | |
| 517 | |
| 518 bool SequentialSubTasksDone::all_tasks_completed() { | |
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519 uint* n_completed_ptr = &_n_completed; |
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520 uint complete = *n_completed_ptr; |
| 0 | 521 while (true) { |
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522 uint res = Atomic::cmpxchg(complete+1, n_completed_ptr, complete); |
| 0 | 523 if (res == complete) { |
| 524 break; | |
| 525 } | |
| 526 complete = res; | |
| 527 } | |
| 528 if (complete+1 == _n_threads) { | |
| 529 clear(); | |
| 530 return true; | |
| 531 } | |
| 532 return false; | |
| 533 } | |
| 342 | 534 |
| 535 bool FreeIdSet::_stat_init = false; | |
| 536 FreeIdSet* FreeIdSet::_sets[NSets]; | |
| 537 bool FreeIdSet::_safepoint; | |
| 538 | |
| 539 FreeIdSet::FreeIdSet(int sz, Monitor* mon) : | |
| 540 _sz(sz), _mon(mon), _hd(0), _waiters(0), _index(-1), _claimed(0) | |
| 541 { | |
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542 _ids = NEW_C_HEAP_ARRAY(int, sz, mtInternal); |
| 342 | 543 for (int i = 0; i < sz; i++) _ids[i] = i+1; |
| 544 _ids[sz-1] = end_of_list; // end of list. | |
| 545 if (_stat_init) { | |
| 546 for (int j = 0; j < NSets; j++) _sets[j] = NULL; | |
| 547 _stat_init = true; | |
| 548 } | |
| 549 // Add to sets. (This should happen while the system is still single-threaded.) | |
| 550 for (int j = 0; j < NSets; j++) { | |
| 551 if (_sets[j] == NULL) { | |
| 552 _sets[j] = this; | |
| 553 _index = j; | |
| 554 break; | |
| 555 } | |
| 556 } | |
| 557 guarantee(_index != -1, "Too many FreeIdSets in use!"); | |
| 558 } | |
| 559 | |
| 560 FreeIdSet::~FreeIdSet() { | |
| 561 _sets[_index] = NULL; | |
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562 FREE_C_HEAP_ARRAY(int, _ids, mtInternal); |
| 342 | 563 } |
| 564 | |
| 565 void FreeIdSet::set_safepoint(bool b) { | |
| 566 _safepoint = b; | |
| 567 if (b) { | |
| 568 for (int j = 0; j < NSets; j++) { | |
| 569 if (_sets[j] != NULL && _sets[j]->_waiters > 0) { | |
| 570 Monitor* mon = _sets[j]->_mon; | |
| 571 mon->lock_without_safepoint_check(); | |
| 572 mon->notify_all(); | |
| 573 mon->unlock(); | |
| 574 } | |
| 575 } | |
| 576 } | |
| 577 } | |
| 578 | |
| 579 #define FID_STATS 0 | |
| 580 | |
| 581 int FreeIdSet::claim_par_id() { | |
| 582 #if FID_STATS | |
| 583 thread_t tslf = thr_self(); | |
| 584 tty->print("claim_par_id[%d]: sz = %d, claimed = %d\n", tslf, _sz, _claimed); | |
| 585 #endif | |
| 586 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); | |
| 587 while (!_safepoint && _hd == end_of_list) { | |
| 588 _waiters++; | |
| 589 #if FID_STATS | |
| 590 if (_waiters > 5) { | |
| 591 tty->print("claim_par_id waiting[%d]: %d waiters, %d claimed.\n", | |
| 592 tslf, _waiters, _claimed); | |
| 593 } | |
| 594 #endif | |
| 595 _mon->wait(Mutex::_no_safepoint_check_flag); | |
| 596 _waiters--; | |
| 597 } | |
| 598 if (_hd == end_of_list) { | |
| 599 #if FID_STATS | |
| 600 tty->print("claim_par_id[%d]: returning EOL.\n", tslf); | |
| 601 #endif | |
| 602 return -1; | |
| 603 } else { | |
| 604 int res = _hd; | |
| 605 _hd = _ids[res]; | |
| 606 _ids[res] = claimed; // For debugging. | |
| 607 _claimed++; | |
| 608 #if FID_STATS | |
| 609 tty->print("claim_par_id[%d]: returning %d, claimed = %d.\n", | |
| 610 tslf, res, _claimed); | |
| 611 #endif | |
| 612 return res; | |
| 613 } | |
| 614 } | |
| 615 | |
| 616 bool FreeIdSet::claim_perm_id(int i) { | |
| 617 assert(0 <= i && i < _sz, "Out of range."); | |
| 618 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); | |
| 619 int prev = end_of_list; | |
| 620 int cur = _hd; | |
| 621 while (cur != end_of_list) { | |
| 622 if (cur == i) { | |
| 623 if (prev == end_of_list) { | |
| 624 _hd = _ids[cur]; | |
| 625 } else { | |
| 626 _ids[prev] = _ids[cur]; | |
| 627 } | |
| 628 _ids[cur] = claimed; | |
| 629 _claimed++; | |
| 630 return true; | |
| 631 } else { | |
| 632 prev = cur; | |
| 633 cur = _ids[cur]; | |
| 634 } | |
| 635 } | |
| 636 return false; | |
| 637 | |
| 638 } | |
| 639 | |
| 640 void FreeIdSet::release_par_id(int id) { | |
| 641 MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); | |
| 642 assert(_ids[id] == claimed, "Precondition."); | |
| 643 _ids[id] = _hd; | |
| 644 _hd = id; | |
| 645 _claimed--; | |
| 646 #if FID_STATS | |
| 647 tty->print("[%d] release_par_id(%d), waiters =%d, claimed = %d.\n", | |
| 648 thr_self(), id, _waiters, _claimed); | |
| 649 #endif | |
| 650 if (_waiters > 0) | |
| 651 // Notify all would be safer, but this is OK, right? | |
| 652 _mon->notify_all(); | |
| 653 } |